This invention relates to an improved luer cap for medical devices, principally for use on medication ports, connecting ports, and injection ports of medical devices.
Many medical devices such as cardiotomy reservoirs, blood sets, and oxygenators have ports for access to the devices. Since many of the devices process a patient's blood for a variety of medical treatments, e.g., oxygenation of blood during a heart-lung bypass operation, it is frequently necessary that a physician, nurse, or medical technician have access to the device to add medication to the patient's blood or to take a blood sample. Because of this need, many medical devices have ports which are covered by a protective cap. When access is necessary, the caps are removed to uncover the port.
The major problem with prior art port caps is the inability to sterilize through the cap once it is placed on a port in the manufacturing process. An additional problem is that, prior to this invention, no luer cap was available through which sterilization could occur and which would not leak air or liquid when subjected to a positive or negative pressure during operation of the device.
The term "luer" is derived from the name of a German instrument maker who developed a medical syringe in the Nineteenth Century. The term "luer-lok" is defined in Dorland's Illustrated Medical Dictionary, 25th Edition, as "a glass syringe for intravenous and hypodermic use, with a metallic tip and locking device to hold the needle firmly in place."
FIGS. 3 and 4 of U.S.A. Standard Z70.1-1955, "Dimensions of Glass and Metal Luer Tapers for Medical Applications," show respectively female luer lock and male luer lock connectors. Burd U.S. Pat. No. 4,133,312 shows a luer lock connection used with a blood tubing set.
The structure of U.S.A. Standard Z70.1-1955, "Dimensions of Glass & Metal Luer Tapers for Medical Applications", (FIG. 4 of the Standard), and the structure of the blood tubing set connector of Burd U.S. Pat. No. 4,133,312 cannot perform the sterilizing function of the present invention since their tubular portions are open. Additionally, the U.S.A. Standard and Burd U.S. Pat. No. 4,133,312 are connectors for fluid flow and cannot perform a capping function like the present invention.
Before this invention, a practice was to supply medical devices with sterile ports covered by protective tabs. Caps for these ports were supplied separately. Before the medical device was placed into operation, the tabs on the ports were removed and the caps put in place. There was concern on the part of medical personnel for maintenance of sterility of the system when the caps were put in place. A reason that medical devices, prior to this invention, were not supplied with the port caps in place was that the gas used to sterilize the medical device could not pass through the cap and reach, and therefore sterilize, the portion of the device (port area) covered by the cap.
Thus, there is a need to provide a luer cap for ports of medical devices through which sterilization can occur and which will not leak air or liquid when subjected to a positive or negative pressure during operation of the device. The ability of the luer cap to not leak air or liquid during positive or negative pressurization of the medical device is significant since many medical devices operate above (positive) or below (negative) atmospheric pressure. If the device is subjected to a negative pressure, and the luer cap leaks, the potential for airborne contamination entering the device is high. If the device is subjected to a positive pressure, and the luer cap leaks, blood or other body fluid could escape from the device to the potential severe detriment of the patient.
A cap which is simple in design is also desirable for ease of molding and manufacture.
It is, therefore, an object of this invention to provide an improved luer cap for medical devices which is of simple design, and when placed on a port of a medical device, the port can be sterilized through the luer cap. It is a further object of this invention to provide an improved luer cap which will not leak air or liquid when subjected to a positive or negative pressure during use of the device.
These objects are satisfied by the present invention which incorporates a luer cap design which is permeable to ethylene oxide gas (ETO) and can be placed on a device prior to ETO sterilization. The design is also capable of withstanding the positive or negative pressures that the medical device may be subjected to during use.